English typos

Just two basic typos ( classical -> classic, Wally -> Waldo)

I didn't remove `python-pytest`, because maybe the error I had is just due to me having Ubuntu LTS and not the most recent ubuntu version.

There are other changes for which I'm unsure whether to make a pull request or not, because I don't know if it's on purpose:
- In order to generate the website doc, the package `python-docutils` needs to be added (but it's not in the list of debian packages in the README)
- adding `website/*.html` and `website/license.txt` to .gitignore removes a lot of the clutter from `git status`, once the website doc is generated.